CDC Reports Double-Masking Can Prevent More Than 90% of Viral Particles Amid COVID-19 Pandemic

Public officials and their staff have been wearing two face masks at many public events recently, but the CDC declined to comment on whether it was worth doing — until now. On Wednesday, the Center for Disease Control and Prevention published a new recommendation saying that wearing a cloth face mask over a surgical mask can improve protection against COVID-19. The advice for "double-masking" is very specific.

The CDC has already been advising Americans to wear face masks whenever they are out in public to avoid spreading or catching the novel coronavirus. Since the beginning, surgical masks and N95 filter masks have been the top recommendation, followed by cloth masks made to certain specifications if necessary. Now, the agency is saying that the best option might be both. Their recommendation is based on a study conducted on lab test dummies with different kinds of masks.

The CDC found that wearing a cloth mask over a surgical mask increases their efficacy by playing to both of their advantages. It ensures a tighter, more secure fit for the surgical mask, which means that there is no room for saliva particles to escape even with prolonged use. The study also examined the difference between wearing a surgical mask as it is made and knotting the ear loops for the specific wearer's face — a practice the CDC referred to generally as "knotting and tucking."

The results showed that a surgical mask by itself worn in the usual way blocked about 42 percent of COVID-19 particles while knotting and tucking blocked about 65 percent. Meanwhile, double-masking blocked 83 percent of the particles.

"We know that masks work," said the report's co-author Dr. John Brooks. "This is about how to help them work better."

Medical experts have raised this concern before, but have never offered this recommendation to resolve it. The FDA's website says that surgical masks "do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the mask and your face."

Surgical masks remain the top recommendation by scientists because they're made of polypropylene, which creates a small electric charge that can catch viral particles either coming or going from the wearer. However, the one-size-fits-all masks are made with a loose fit, as experts are now ready to admit.

The official CDC recommendation is now to double-mask if possible, or to twist and knot a surgical mask's fittings to ensure it is secure. As always, avoiding crowded places and social distancing as much as possible remains the top recommendation.